Pfaff creative 4874 Instruction Manual page 142

Problem
Seam puckers
Fabric is not being
fed evenly
9-6
Cause
Thread tension is too tight
The differential feed is set
incorrectly
The thread has jammed because
of incorrect threading
The stitch length is too short
The presser foot pressure
is too low for heavy fabric
The presser foot pressure is too
high for light fabric
Remedy
Reduce thread tension.
Adjust differential feed (see page 2-34).
Thread correctly.
Increase stitch length (see page 3-4).
Increase presser foot pressure (see page 2-25).
Reduce presser foot pressure (see page 2-25).